the black wire from that bunch goes to the switch.
And the other side goes to the plug, right?
Black is the hot wire, white is the common, and green is the ground.
I'd use the small black wire to the other side of the switch.
Connect the big white wire to the little white wire.
Take 2 red wires from the ballast... like that litte picture I tried to make, and connect them to the red wire.
Take the other 2 red wires from the ballast and connect them to whatever color wire you want.
Take the yellow from the ballast and connect it to the yellow wire.
That's all you need. you won't need the other wires.